Hello,
Do you Know Ebay? I don´t know if you speak German, but Ebay Germany offers you a wide range of bycicle equipment.
You can find new or second hand. There are shops and individual sellers.
Last year I have bought my first bags for my bike. I friend recomend me a very important mark: Ortlieb.
You can find this products under:
www.ortlieb.de (German, English and French)
good luck